Long road trip, need help...

[landmariner]

If you plan to visit both Canyonlands and Arches, as well as cover the over 500 miles between Moab and Las Vegas (including 'detours' to the two parks, then an additional overnight stop on the night of the 22nd is pretty much a necessity. Since both of the parks you've named are in the Moab area, that overnight stop will also need to be much closer to Moab than to Las Vegas. The Salina UT area offers a wide array of motels, both chain and boutique, in a number of price ranges. At roughly 215 miles from Moab (again, including getting to the two NPs near Moab) it could still be reached in a relatively easy day. Then from Salina to Las Vegas, you'll have the opportunity to visit Zion NP as well.

AZBuck

There is a hotel/motel right off the interstate and across the huge parking lot is a decent restaurant. Haven't been there in a few years but the best tamales ever.
Super 8 by Wyndham Salina/Scenic Hills Area and
El Mexicano Restaurant - Salina

Rt. 12 is one of the best scenic drives around. Near Escalante is the Kiva Koffeehouse, for some good coffee and grub, and anchored by three canyons.

[glc]

I would really try to make the time to drive UT-12 between Torrey and Bryce Canyon. You have a great car for it!

[ZeeBabar]

Once again, thank you all. Perhaps I will do a trip report as I go on.